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Metal Detector Circuits
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Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
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AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
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Data Bus Circuits
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RF Converter Circuits
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voltage to frequency
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Video Wall circuits
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8051 / 8052
PCB CAD Software
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555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
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Regulated Power Supply
4 Band Resistor
5 Band resistor
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Automotive Alarm Circuits
Car Lighting Circuits
Car Parking Aid Circuits
Car Audio Circuits
Car Bike Circuits
Voice-activated toy car circuit
Electric cars represent the voice circuit principle, when to speak, against sound signal received by a drop in the body into a microphone BM and telecommunications weak number,
125 Motorcycle electronic ignition circuit diagram
EXT connected AC magneto produced. Rectified by D1 stored in C1, and rectified by D4, R9, C7, C8 filtering, power supply to the integrated circuit IC, the D3 then turn off the
Car battery monitor III
The circuit is quick and easy to put together and install, and tells you when battery voltage falls below the set limit as established by Rl (a 10,000-ohm potentiometer). It can indicate, via LED 1, that the battery may be defective or in need of change if operating the starter causes the battery voltage to drop belciw the present limit.
Car Ice ararm circuit
The circuit uses a thermistor and three sections of a LM3900 quad op amp IC. When the temperature drops to 36Â°F the LED indicator flashes about once each second. The flashing rate increases as temperature drops to 32Â°F when the LED remains on. Amplifier I compares the thermistor's resistance to the resistance of the standard network connected...
When the lights of an on-coming car are sensed by photo-transistor Ql, things get going. Sensitivity is set by the 22-megohm resistor, R5, to about half a foot-candle. The relay used has a 12-volt, 0.3A coil.
This circuit switches car headlights to the low beam state when it senses the lights of an on-coming car. The received light is very low level and highly directional, indicating the use of a lens with the detector. A relatively large amount of hysteresis is built into the circuit to prevent "flashing lights."
Here is a simple tachometer circuit for use with a hand-held DVM or portable chart recorder. A novel feature is that the source frequency pulse/rev rate can be directly set on a ten-turn potentiometer to provide a convenient calibration of one V per 1000 rev/min. This is particularly useful when measuring a shaft or engine speed by sensing...
Analog Tachometer Readout
The analog display consists of a frequency/voltage converter (IC12) and bar-graph segment drivers IC10 and IC11.
Delayed headlights circuit
This circuit keeps an automobile's headlights on temporarily. It also will turn the lights off, even if you forget to flip the light switch. The circuit's shut-off delay is actuated only after both the ignition and light switches have been on, and only if the ignition switch is turned off first. If the light switch is turned off first, no delay...
Ignition monitor strobe
Figure A shows the circuit of a direct-trigger timing light. The trigger voltage is -taken from the car's ignition circuit by a direct connection to a spark plug. A circuit using an inductive pickup is shown in Fig. B. A trigger transformer is used to develop the high-voltage pulse for triggering. The triggering circuit consists of Tl, CI, SCR1,...
Pulses from the distributor points are passed through a current limiting resistor, rectified, and clipped at 4 volts. Via Q1 and the diode pump, a dc voltage proportional to engine rpm is presented to RV1; the sharp transfer characteristic of a CMOS gate, assisted by feedback, is used to enable the oscillator formed by the remaining half of the...
Universal wiper delay
ICl is connected in the astable mode, driving RLA, C3, Dl, and D2 prevent spikes from the relay coil and the wiper motor from triggering ICl. VR2 is adjusted to give the minimum delay time required. VR1 is the main delay control and pro vides a range of from about 1 second to 20 seconds. SW1 is an override switch to hold RLA permanently on (for...
Courtesy light extender
Most car door switches are simply single-pole switches, with one side grounded. When the door is opened the switch grounds the other line thus completing the light circuit. In a car where the negative terminal of the battery is connected to the chassis, the negative wire of the unit (emitter of Q2) is connected to chassis the positive wire (case...
High speed warning device
A1 amplifies and regulates the signal from the spark coil. A2 converts frequency to voltage so that its output is a voltage proportional to engine rpm. A3 compares the tachometer voltage with the reference voltage and turns on the output transistor at the set speed
Auto battery current analyzer
This op-amp analyzer can measure the current drawn by any device in a car. The analyzer works by measuring the very small voltage that develops across the battery cables when current flows
Windshield wiper controller
This circuit provides complete speed control over car"s windshield wipers. They can be slowed down to any rate even down to four sweeps per minute
Headlight delay unit
This circuit will operate a car"s headlights for a predetermined time to light up the driveway or path after the driver has left the car. SQl is pushed and Q2 is turned on closing the relay and turning on the car"s headlights. Cl begins to charge through VR1 until Q1 turns on, turning Q2 off
Windshield washer fluid watcher
This circuit relies upon the minute current between two conductive probes suspended in a washer fluid reservoir
Car battery condition checker
This circuit uses an LED and 4081 CMOS integrated circuit. The variable resistor sets the voltage at which the LED turns on. Set the control so that the LED lights when the voltage from the car"s ignition switch drops below 13 volts
An op-amp comparator is used to compare the converter output with a dc threshold voltage. The circuit flashes the LED when the input frequency exceeds 100 Hz. Increases in frequency raise the average current out of terminal 3 so that frequencies above 100 Hz reduce the charge time of C2, increasing the LED flashing rate
When the turn signal switch SI is closed, lamp #1 will be activated and capacitor Cl will charge to the triggered voltage of Ql. As soon as the anode voltage on Ql exceeds its gate voltage by 0 V, Ql will switch into the low resistance mode, thereby triggering SCR1 to activate lamp #2 and the second timing circuit. After Q2 switches into the low...
12 V battery charger
This circuit is a high performance charger for gelled electrolyte lead-acid batteries. Charger quickly recharges battery and shuts off at full charge. Initially, charging current is limited to 2A. As the battery voltage rises, current to the battery decreases, and when the current has decreased to 150 mA, the charger switches to a lower float...
In operation. the alarm circuit allows a 0-47 second time delay, as determined by the Rl/Cl combination, after the switch is armed to allow the vehicle"s motion sensor to settle down. This allows you time to get a bag of groceries out of the trunk and not have the hassle of juggling the groceries and the key switch at once. During the time...
See (a) for the timing information for the alarm circuit in (b). When leaving your vehicle, flip the arming switch and close the door to arm the device. Subsequent opening of an entrance triggers both timers. After the expiration of the entry delay timer, the alarm sounds for a time determined by the second timer. The value of R should be...
The ignition substitute provides a constant power source for the ignition coil. Its frequency, 0.5-1.0 kHz, is that used by an 8-cylinder engine with an idling speed of 650 RPM, and the unit provides a rapid spark at a 17% duty cycle, while staying within the power dissipation limits of the components. The circuit consists of a 555 timer IC...
This circuit holds on the internal light for approximately one minute after the car doors are closed. When the door contacts open, a + VE pulse is applied to the base of Tl. This transistor turns on, turning off T2 and charging the 10-llF capacitor. T3 turns on, holding on the internal light.
With both the ignition and the car lights on, piezo transducer BZl draws no current and remains silent. With only the ignition on, diode Dl is reverse-biased and so prevents current flow through BZL. However, when the lights are on and the ignition is off, the transducer becomes energized and sounds to alert you to tum the lights off.
This locater is made up of two parts. The first is an rf oscillator, whose circuit is shown in Fig. 8-4a. The second is a sensitive receiver shown in Fig. 8-4b. The heart of the oscillator is a 555 timer !C. Tank circuit C2 and L1 is used to tune the transmitter. The antenna is coupled to the transmitter through C3. A telescopic antenna or a...
The heart of the circuit is ICZ, a 4046 micropower phase-locked loop (PLL). The incoming signals are fed to the PLL after being buffered by IC1a and its associated components. The frequency of the incoming signal is multiplied by either 90, 60, or 45, depending on the setting of the cylinder select switch, SZ. That switch selects the proper...
This circuit disables the air conditioner compressor when additional engine power is required. It does so by monitoring the engine vacuum at the intake manifold. Ifthe vacuum drops to 40% of its normal level, the compressor clutch is disabled, removing the air conditioner load from the engine. After the engine returns to normal vacuum level,...
The monitor senses an ajar door and, if the situation isn"t corrected within 20 seconds, sounds a beeping alarm. The circuit is controlled by a magnetic reed switch and magnet on the door. With the door closed, the switch is closed and the alarm is disarmed. Opening the door opens switch, Cl starts charging up through Rl. Approximately 20...
A monolithic 555-type timer is the heart of this simple automobile voltage regulator. When the timer is off so that its output at pin 3 is low, the power Darlington transistor pair is off. If battery voltage becomes too low, less than 14.4 V in this case, the timer turns on and the Darlington pair conducts. Can be any general purpose Silicon...
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial